Drivers of a Russian convoy of trucks carrying humanitarian aid for Ukraine show the contents of their trucks at a camp near Kamensk-Shakhtinsky, in Russia's Rostov region today. Dozens of heavy Russian military vehicles amassed on Friday near the border with Ukraine where a huge Russian convoy with humanitarian aid came to a halt as Moscow and Kiev struggled to agree border crossing procedures.

Officials from Ukraine’s border guards crossed into Russia to inspect the convoy of trucks stopped near the border that Moscow says is carrying humanitarian aid for conflict-ridden eastern Ukraine.

A Ukrainian border guard official told the Associated Press that the convoy is being examined while officials from the International Committee of the Red Cross (ICRC) look on. He said that 41 Ukrainian border guard representatives and 18 customs officials started their work on Friday morning in Kamensk-Shakhtinsky, a town less than 20 miles from the border.

Tensions have been high between Ukraine and Russia since Russia's annexation of Crimea, which involved so-called “little green men” who turned out to be well-trained Russian military personnel. Kiev fears the aid convoy could be used as a pretext for strengthening pro-Russian rebels or even lead to a full-scale conflict.

Although humanitarian aid is desperately needed in eastern Ukraine, with hundreds of thousands displaced by the fighting between Ukrainian government forces and pro-Russia rebels, it remains unclear who the beige-clad truck drivers really are. When questioned about their backgrounds by the Guardian, one driver gave conflicting information:

In general, the men did not want to speak about who they were or how they had come to be involved in the convoy. One said he was a volunteer from a non-governmental organisation, but clammed up when asked for the name of the organisation.

“I’m being paid to do a job here, not to stand around talking to journalists,” he said when pressed, and then looked sheepish when reminded he had just claimed to be an unpaid volunteer.

Over the past two days, convoy drivers have allowed journalists to look into trucks of the drivers' choosing, showing the journalists boxes of new sleeping bags and buckwheat. Some observers have questioned why some of the trucks are not at full capacity:

The lack of information has thrust the ICRC into an uncomfortable position with the need to get aid to eastern Ukrainians but not knowing what Russia is planning. This has created worries that any move made by the ICRC could result in serious political implications.

“Putin practices the old KGB technique of maskirovka, masking and deception, in everything he does in this conflict,” Kimberly Marten, a professor at Barnard College and Columbia University, told the Monitor via e-mail. “His goal is to keep people guessing, to create disunity among the Western community, and to buy time before deciding on his next move.”

While the convoy has not yet reached the border, journalists reported seeing Russian military vehicles cross into Ukraine yesterday separately from the humanitarian convoy. A reporter for the Guardian said that he witnessed the passage of “a column of 23 armoured personnel carriers, supported by fuel trucks and other logistics vehicles with official Russian military plates” into Ukraine.

Ukrainian military spokesman Oleksiy Dmytrashkivsky told Reuters that such crossings have become common, and support claims made by the Ukrainian government of Russian involvement in the conflict.

"These movements into Ukrainian territory take place practically every day with the aim of provoking [the Ukrainian side]. Last night was no exception. Some armored vehicles came across. We are checking on the quantity and the number of people who came over," he said.